to not V

[sitifan]

look through somebody/something (phrasal verb)
to not notice or pretend not to notice someone you know, even though you see them
http://www.ldoceonline.com/dictionary/look_1
look through sb
to not notice someone that you know, or to pretend that you have not noticed someone, even though you are looking directly at them
http://dictionary.cambridge.org/define.asp?key=look.through*2+0&dict=P

Why use "to not V"? Why not use "not to V"?
What's the difference in meaning or style between the above two structures?
_________________
Thank you very much for your reply.

[Raymott]

Originally Posted by sitifan

look through somebody/something (phrasal verb)
to not notice or pretend not to notice someone you know, even though you see them
http://www.ldoceonline.com/dictionary/look_1
look through sb
to not notice someone that you know, or to pretend that you have not noticed someone, even though you are looking directly at them
http://dictionary.cambridge.org/define.asp?key=look.through*2+0&dict=P

Why use "to not V"? Why not use "not to V"?
What's the difference in meaning or style between the above two structures?
_________________
Thank you very much for your reply.

All the other definitions for verbs begin with "to ... ". Why do you want them to change their style for negative meanings? Usually there's no difference between "to not do something" and "not to do something".
In this case they're just being consistent.